In November 2002, the oil tanker Prestigebroke apart and sank, spilling about 20 million gallons of bunker oil off the coast of northern Spain. Workers, many of whom were local fishermen, participated in a massive clean-up effort. The Prestige oil spill is unique among the 38 supertanker oil spills over the past 50 years -- this is the only oil spill in which workers have been studied long-term for illnesses.

Today, in the Annals of Internal Medicine, a well-respected Spanish research team has published their latest findings. Their paper is worth reading, since it sheds some light on the health effects in oil spill clean-up workers, and may be relevant to the men and women working to clean up the BP Gulf oil spill.

This study, entitled "Health Changes in Fishermen Two Years After Clean-up of thePrestige Oil Spill" (abstract | full text), evaluated 678 exposed and unexposed fishermen and women. The main findings include:

Oil-exposed study participants are significantly more likely to have persistent lower respiratory symptoms (such as cough and shortness of breath), and also on average have more than a two-fold higher level of an inflammatory biological marker (8-isoprostane) in their exhaled breath (smokers and asthmatics were not included in this test to avoid confounding the results).

Oil-exposed non-smoking participants have significantly higher rates of chromosomal abnormalities in their white blood cells, including chromosomal deletions and translocations. This type of chromosomal damage has been associated with increased cancer risk and has been reported previously in other workers exposed to benzene, which is a constituent of oil.

The longer workers were involved in oil clean-up activities, the more likely they were to have elevated levels of inflammatory markers in their exhaled breath, respiratory symptoms, and more chromosomal abnormalities in their blood cells.

There are differences between the Prestige oil spill and the BP Gulf oil spill. First, the Gulf spill is much larger - about 10-times more oil spilled into the Gulf compared with the Spanish oil spill, and fresh oil was continuing to emerge and evaporate (contaminating the air) for months. Second, dispersant chemicals were heavily used in the Gulf (about 2 million gallons), whereas these chemicals were not used in large amounts during the Prestige clean-up. Third, the Gulf spill involved light crude oil whereas the Prestige spill was heavy bunker oil - the ingredients of the two are mostly the same, but the relative proportions of those ingredients differ a lot. Fourth, the Gulf clean-up involved burning oil on the water surface, whereas the Prestige spill did not. Finally, some of the Prestige workers used pressure hoses to clean rocky beaches, potentially creating an oily aerosol in the air, whereas that technique has not been used in the marshes and sandy coastline of the Gulf.

The bottom line is that we can’t assume that all the findings of this study will necessarily apply to workers in the Gulf, but the study certainly raises serious concern about long term respiratory and cancer risks to oil spill clean-up workers, and underscores the need to protect workers, provide them with access to medical care, and follow-up their health status in the future. It also adds to a growing body literature identifying the increased risks to fishermen working on oil-spill clean-ups. That's why it is so important that the newGulf Worker Study that is being launched by the National Institute of Environmental Health Sciences (NIEHS) is fully-funded and successful. We need to know if these workers are getting sick.